Tuberculosis (TB) is an infectious disease that kills more adults than any other infectious disease worldwide. Every year, 8.9-9.9 million new cases of TB are estimated by the World Health Organization to occur globally. The disease is caused by bacterium Mycobacterium tuberculosis, which can reside in an infected host for many years. Most infected people remain latently infected with the organism, but a subset of infected individuals will reactivate the infection and develop active disease. Timely treatment of those who develop active disease is critical for preventing further transmissions to others. Treatment requires reliable, rapid diagnosis of the disease.
The problem is that in most countries endemic for TB, the diagnosis of the disease is hampered by the lack of resources to culture the organism, which is especially needed to diagnose drug-resistant forms of the disease. As such, in most countries, including in the United States, the treatment of the disease is often initiated empirically, without the knowledge of the drug-susceptibility of the causative agent. In someone who has drug-resistant TB, such a method of treatment often fails.
There is a need in the art for methods of determining whether an individual who is being treated for TB is responding to such treatment.